248 
American Fossil Cyads. 
sibility, if not the manner as well, of angiosperm development 
directly from filicinean forms.” 
With the views above expressed the reviewer heartily agrees 
and recognises in the “ flower ” of Cycadeoidea a development parallel 
and analogous to that of an Angiosperm. From the data to hand as 
to the derivation by way of extreme reduction of the sporophylls 
of modern Cycads from those of Pteridosperms, we must regard 
the simple one seeded megasporophyll of Cycadeoidea as a striking 
instance of excessive reduction while retaining the radial symmetry 
of structure which it appears to inherit from the sporangium¬ 
hearing pinnule in the far-hack Fern-ancestor ; hut this condition 
is far removed from the highly advanced and modified structure of 
the Angiospermous carpel. Still less does the microsporophyll of 
Cycadeoidea bear any resemblance to that of an Angiosperm, which 
latter, in course of its probable great reduction and simplification, 
has, like the megasporophyll of Cycadcoidece retained primitive 
radial structure. Nevertheless, that the highly reduced and con¬ 
gested cone of Cycadeoidea is well on its evolutionary way towards 
the “ flower ’’-structure of an Angiosperm, as shewn by the mode of 
juxtaposition of the mega- and microsporophylls and by the cyclic 
arrangement of the latter, the reviewer verily believes; yet really 
not more so than, if as much as, the cones of modern Cycads, for 
he still regards the cone of Cycadeoidea , as, on the whole and 
essentially, more primitive , than that of modern Cycads, with 
the exception of the female side of Cycas. 
This epoch-making work, for it is nothing less, should be studied 
by all interested in the evolution of plants, for embedded in its 
pages, and, indeed, involved in the very nature of the subject matter 
treated of, are problems of wide and general importance for the 
student of evolutionary development. For example much room for 
thought is afforded by the question, how far and to what extent 
is “ reduction or simplification of structure an accompaniment of 
evolution ? ” 
The book contains 246 pages of text, 138 text-illustrations, 50 
plates of excellent photographs, with a very full description of each ; 
a Bibliography, in which 219 works are cited, and an adequate 
index. 
Dec. 4th , 1906. 
W.CAV. 
